i just got my pro melt, when set at 675 it will cool down to 550 before kicking in and will heat up too 750 before it cut's out is this normal?it sure sucks to try and cast with the temp moving around like that. but i'm new at it so maybe its just me?
RCBS Pro Melt thermostat control issue
- Thread starter mooseman1
- Start date
That is about normal, it is amazing how much temperature swing there is.
The thermostats on the pro melt and the Lyman pots as well as the Lee pots have very loose tolerances and are ball park temperatures at best.
The worst one is my little lee 10 lb bottom pour pot. Since there is only 10 lbs of lead and say you use 3 lbs and then decide to add a 1 lb ingot to top it up the temp will go all the way down to 550 deg F from 750 and heat until it gets to 825 before shutting off again.
I made a PID controller for my lead pots and the temperature swing is about 50 deg at worst.
http://www.canadiangunnutz.com/forum/showthread.php?t=480814&highlight=PID
If I set the controller to 800 F for casting hollow points it will come on until it gets to 800 F and the element will turn off but the temp will continue to rise about another 10 deg or so and as soon as it drops again to 795 it turns back on. It might go as low as 775 as it heats back up but a swing of 40-50 deg is a heck of a lot better than 200 deg swing.
As you continue to use the pot the controller will learn the temp swing and try to compensate for it and the temp swing will become less.
When I cast I never put back any sprue cut off lead or top the 20 lb pot up, just pour and when I want a break after 30 min. or so and the pot is nearly empty, then I put more lead in that has been pre-heated on a burner or in another pot. Put the mold on the hot plate, wait about 5 min to come up to temp at most and away I go again.
The thermostats on the pro melt and the Lyman pots as well as the Lee pots have very loose tolerances and are ball park temperatures at best.
The worst one is my little lee 10 lb bottom pour pot. Since there is only 10 lbs of lead and say you use 3 lbs and then decide to add a 1 lb ingot to top it up the temp will go all the way down to 550 deg F from 750 and heat until it gets to 825 before shutting off again.
I made a PID controller for my lead pots and the temperature swing is about 50 deg at worst.
http://www.canadiangunnutz.com/forum/showthread.php?t=480814&highlight=PID
If I set the controller to 800 F for casting hollow points it will come on until it gets to 800 F and the element will turn off but the temp will continue to rise about another 10 deg or so and as soon as it drops again to 795 it turns back on. It might go as low as 775 as it heats back up but a swing of 40-50 deg is a heck of a lot better than 200 deg swing.
As you continue to use the pot the controller will learn the temp swing and try to compensate for it and the temp swing will become less.
When I cast I never put back any sprue cut off lead or top the 20 lb pot up, just pour and when I want a break after 30 min. or so and the pot is nearly empty, then I put more lead in that has been pre-heated on a burner or in another pot. Put the mold on the hot plate, wait about 5 min to come up to temp at most and away I go again.
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Wow , what do you charge for making one
?you should post it on the (clever invention tread)
Never thought of posting it in the clever thread, good idea.
I have had lots of requests to make them and so I decided to do the in depth "how to" in the summer time so anyone can do it. I have helped various gunnutz with the wiring especially if the PID controller is slightly different. Honestly the wiring is easy, it the initial setup of the thermocouple and how the PID controller uses it that is a bit tricky.
I just finished a dual model version in one box, left side is independent of the right side, one controls the pot and the other one controls a hot plate that I pre heat the mold on and lead ingots. Works excellent.
I have had lots of requests to make them and so I decided to do the in depth "how to" in the summer time so anyone can do it. I have helped various gunnutz with the wiring especially if the PID controller is slightly different. Honestly the wiring is easy, it the initial setup of the thermocouple and how the PID controller uses it that is a bit tricky.
I just finished a dual model version in one box, left side is independent of the right side, one controls the pot and the other one controls a hot plate that I pre heat the mold on and lead ingots. Works excellent.
